Method of treating hollow glass articles



Ap 1939- o. G. BURCH METHOD OF TREATING HOLLOW GLASS ARTICLES Filed Dec. 9, 1938 OGCBjavch INVENTOR. BY 1 A74 ATTORN s.

Patented A... 18, 1939 Oscar G. Burch, Alton, 111., assignor to Owenslliinois Glass Company,

omo

a corporation of Application December 9, 1936, Serial No. 114,910 2 Claims. (01. ss-ss) The present invention relates to improvements in the method of treating the interior surfaces of hollow glass articles and more particularly to a method comprising introducing an acidic gas 5 into the article as it is blown into final form.

The character of the glass generally employed in the manufacture of bottles and jars, 'etc., contains various quantities of alkali. When the articles are fllled with an aqueous solution or ex- 10 posed to humid atmosphere, the alkali at and near the exposed surfaces leaches out. The leaching out of the alkali and consequent corrosion of the glass has a deleterious eifect on the contents particularly when the product is a li chemical reagent. Further, it causes the glass to become cloudy, thereby affecting its. transparency.

Various methods of treating the interior surfaces of containers have been employed to inao' crease the resistance of the glass against weathering, such methods generally being employed after the formation of the article. An object of this invention is the provision of a method whereby a predetermined amount of an acidic as gas may be introduced into a partially or completely -formed article prior to removal thereof from the forming machine.

Other objects and advantages will be in part apparent and in part pointed out hereinafter.

30 In the drawing:

' Fig. l is a sectional elevational view through one head of a bottle forming machine of the type illustrated in La France Patent a t-1,185,687

dated June 6, 1916, showing my invention em- 35 bodied therein;

Fig. 2 is a sectional plan view of the cams for controlling the mechanism; and

Fig. 3 is a detail vertical sectional view through the valves shown in Fig. l.

4.0 Referring to Fig. 1 of the drawing, I have illustrated myinvention as applied to a standard Owens type bottle machine such as shown in the patent to La France, No. 1,185,687, and which comprises a mold carriage 5 mounted for rotation 5 about a vertical central column B'by means of a gear I through which power is supplied from a source notshown. A series of finishing molds 9 mounted for rotation with the mold carriage 5 are. adapted to register with cooperating dip- 5 ping heads 9 individual thereto. Vacuum for charging the blank forming molds (not shown) is supplied to the heads 9 from a chamber lli formed within the central column 9. The chamber II is in constant communication with a sec- 5 nd chamber ii formed in a member l2 which is secured for rotation with the frames supporting the blowing heads on the mold carriage.

Air under pressure for expanding the blank into final form in the finishing mold 9 is supplied (from a source not shown) to a chamber it formed adjacent the chamber ill in the column 6. A corresponding chamber It in the rotating member l2 communicates with a blowing valve l5 arranged thereon and which controls the supply of air to each head 9 through a pipe 10 it. Air from the pipe I. is directed into the bottle cavity ll in the head through a blow slide it and passage l9 whichform a part of the standard head construction.

A chamber 29 formed adjacent the chambers i|"and I9 is supplied (from a source not shown) with an acidic gas such as, for instance, sulphur dioxide, hydrogen chloride. carbon dioxide, or a mixture of such acidic gases which, when combined with the blowing air during the forming operation will tend to neutralize the excess of alkali brought to or near the surface of the glass during the forming process. thus inhibiting to a considerable degree subsequent hydrolysis of the glass by moisture of the atmosphere or by liquids contained within the bottle. A chamber 2i within the rotating member i2 serves to connect I the chamber 29 with a gas control valve 22 which is mounted on an upwardly extending hollow support 29 and in vertical alignment with the valve ii. The valve 22 is connected to the blowing air pipe it by a branch pipe 24 in which a check valve 25 is placed. A similar check valve 26 is mounted in the pipe it near the control valve ii. The check valves 25 and 29 are open in the direction indicated by the arrows and prevent the possibility of a premature mixture of the gases when either control valve is open.

A bell-crank lever 21 pivoted at the periphery of the member l2 has its upper end disposed 40 between the stems of the valves l6 and 22 for alternately actuating them to supply either blowing air or gas to the mold cavity. The lower end of the lever 21 is provided with a cam roll 28 adapted to engage a blowing air control cam 29 and a gas control cam 30 (Fig. 2). The blowing air control cam 29 is adiustably mounted on the central column 6 to control the length of the final blowing operation. The gas control. cam 90 is also adjustably mounted to vary the point at which the application of gas to the container is controlled during the forming process as will be described presently.

The cycle of operationof a machine of the character Just described includes delivering a 56 charge of molten glass to a blank forming mold (not shown), compacting the glass therein to form a completed blank or parison by momentarily opening the blowing valve l5 by means of a pull earn 3! (Fig. 2) and upon completion transferring the blank to a finishing mold. The parison, after a suitable reheating period within the closed finishing mold, is expanded to final form by the opening of the blowing valve l5 by the cam 29. The temperature of the glass at this point is relatively high and may vary from 1400 to 2200f R, which renders the glass substantially plastic. While the glass is in this plastic state and is held against the walls of the mold cavity by internal air pressure, the gas control valve 22 is opened by means of the cam and a predetermined amount of gas under pressure is admitted through pipes 24 and It to the mold cavity. The blowing valve I5 is then reopened and the final blow completed, after which time the glass has cooled sufliciently for the article to be removed from the mold".

' When the acidic gases reach the interior of the bottle, a coating of a neutral salt is formed on the surface of the glass as a result of reaction of the'gases with the alkali present thereon as well as any near the surface, and thereby increases the resistance of the glass surface to the action of aqueous and acidic solutions and to weathering action. After proper annealing the bottles may be washed to remove any traces of neutral salts due to the reaction of the gases with the alkali from the glass.

Various changes in the arrangement of the several parts and manner of application may be resorted to without departing from the spirit of the invention or the scope oi the appended claims.

I claim:

1. The method of producing a hollow glass container from a pariscn in a finishing mold, which consists in expanding the parison to the form of the completed container, and, substantially simultaneously with such expansion but prior to opening of the finishing mold, introducing an acidic gas into the container whereby to men-- iii 

